A LEAGUE OF THEIR OWN: St. John’s coach Steve Lavin (left) and D’Angelo Harrison could soon be playing in a new, basketball-centric conference, because a source said the seven schools that don’t play FBS football are on their way out of the Big East.Paul J. Bereswill

A LEAGUE OF THEIR OWN: St. John’s coach Steve Lavin (left) and D’Angelo Harrison could soon be playing in a new, basketball-centric conference, because a source said the seven schools that don’t play FBS football are on their way out of the Big East. (Paul J. Bereswill)

The end of an era came the old fashioned way, on a telephone conference yesterday morning in which the presidents of the seven Catholic schools that comprise the core of the Big East informed commissioner Mike Aresco they have decided to break away from what once was the best basketball conference in the country, multiple sources told The Post.

The seven schools — DePaul, Georgetown, Marquette, Providence, St. John’s, Seton Hall and Villanova — will look to add five schools and reconstitute themselves as a basketball-centric league with schools located primarily in urban Northeast markets. The schools of keenest interest to the seven are Butler, Dayton, St. Louis and Xavier, with Creighton, Gonzaga, St. Mary’s and La Salle also on the radar.

In other words, the Big East, by whatever name, is going back to its roots.

The official announcement, which will come in a statement from the seven schools, could be delayed until they decide what exit route to take. Those seven schools must decide whether to leave as one or to dissolve the conference.

A source with direct knowledge of what was discussed on the call said Aresco was working to avoid the second option because it would be more legally messy. But there is no question the seven schools are leaving.

This split is not about finances. It’s philosophical. The “Catholic Seven” are done associating with schools that field big-time college football and pray at that altar.

“It was the first time I heard [Aresco] a little down,’’ one person who had direct knowledge of the conference call said. “He wasn’t trying to spin it.’’

If the seven schools break away, they would not have to pay any exit fees, but they wouldn’t receive any revenue from the exit fees to be collected from exiting schools Louisville, Pittsburgh, Rutgers, Syracuse and West Virginia. They also would forfeit the Big East name and an automatic berth in the NCAA Tournament.

If the seven opt to dissolve the conference, all 10 current Big East schools (Cincinnati, Connecticut and South Florida are the others) would share any assets. The league would lose its automatic bid in the tournament and all of its agreements — such as the deal to play in the Garden — would be voided.

A source close to those seven told The Post they intended to keep their postseason tournament in the Garden. That source said the Garden would welcome a league with the likes of St. John’s, Georgetown, Butler and Xavier.

“That league … needs the Garden for legitimacy,’’ said the source.

Although this split is based on philosophical differences, the new league will have to address financial concerns. Non-football Big East members receive $1.6 million annually from its TV deals. Exactly what numbers a new Big East — call it the Great Northeast — could command is uncharted territory.

For comparison, Atlantic 10 schools receive about $750,000 annually in what are described as media rights fees. The new Big East likely would launch its own network and sell off marquee games. St. John’s could be uniquely positioned in this scenario because it is one of just six schools that produces its own HDTV broadcasts which can be viewed on TV, computers and smartphones.

The fate of schools such as Connecticut, Cincinnati, South Florida and Temple remains uncertain. They could merge with schools such as Boise State, Central Florida, East Carolina, Houston, Memphis, San Diego State, SMU and Tulane to form a glorified Conference USA/Mountain West.

Glory was once the domain of the Big East. Founded in 1979, it quickly rose to prominence as the premier basketball conference in the nation, the only league ever to send three teams to the same Final Four. When Georgetown, St. John’s and Villanova played in the 1985 Final Four, the mere suggestion that one day the league would dissolve would have been laughable.

By yesterday morning, led by St. John’s president Donald J. Harrington and Georgetown president Dr. John. J DeGioia, the Catholic seven had decided the time was right. The schools will look to sell their marquee games to networks such as ESPN and CBS.

With the seven Catholic schools taking this step, the move to five super conferences is all but complete. There still could be some realignment — Connecticut is desperate for an invitation to the ACC. But the new map of college athletics has been drawn — or in the Big East’s case, redrawn.